Feasibility Study for a National Domestic Biogas Programme in - SNV

Feasibility Study for a National Domestic Biogas Programme Burkina Faso
3 Feasibility assessment
3.1 Technical feasibility
Given the history of biogas technology implementation and the lessons learned in
Burkina Faso, criteria for the selection of an appropriate technical design for “the”
initial continues feed fixed dome biogas plant in Burkina Faso are determined by the
following 18 parameters:
1. Design and construction method is adaptable to local or regional available
construction material.
2. Main criteria for site selection are the convenience of operation and the
integration of overflow utilization in the existing or in future improved
integrated livestock farming system.
3. Gas tight (pressure tested) construction of gas storage and adequate volume
of digester guarantees that the biogas supply from a family size biogas plant
is able to meet about 90% of the energy requirement for cooking (on annual
basis) for a typical household with few amount on animal dung, at least dung
from 2 Tropical Livestock Units (TLU = 250 kg of animal weight).
4. Make possible with adequate gravity filling device and stable connection that
feeding of the biogas plant is convenient and all available dung and urine
enter the digester resulting in higher gas production and high nitrogen
content of overflow.
5. The design allows encouraging the use of more organic matter than animal
manure alone.
6. Provide sufficient access to maintain manhole, overflow point and
displacement tank in general.
7. Minimize technical maintenance requirement.
8. Daily feed and operation of biogas plant is acceptable for both genders.
9. Available grey-, yellow- and waste water, urine and overflow can be used to
dilute dung; no extra water additive should be required in normal operation.
10. Low flush, pour flush or no flush toilet connection (black- or brown water) is
technically possible at all time.
11. Shortcut of inflow to outflow is avoided to guarantee a minimum retention
time in the digester for energy and hygiene performance.
12. Easy understandable but qualified construction allows rural skill development
and encourages the establishment of new craftsmen jobs in rural areas.
13. Overall investment costs are accessible to the target group, supported by
financial instruments.
14. The selected average slurry volume permits flexible retention times from 2-3
TLU to 8-10 TLU and connection of toilet facilities (universal basic plant
type).
15. Effluent utilization is addressed within the handover training, considering a
wider range of options, aiming optimized nutrient recovery and convenience
in operation; storage overflow could be combined in gravity flow with
compost pit system and/or ferti-irrigation channels and/or drying beds.
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